Helicobacter pylori infection is a risk factor for constipation in patients with Parkinson's disease: A multicenter prospective cohort study

BACKGROUND AND AIMS

Constipation is one of the most common nonmotor symptoms (NMSs) of Parkinson's disease (PD). The infection rate of Helicobacter pylori (HP) is greater in PD patients. This study was a multicenter prospective cohort study in which propensity score matching (PSM) was used to determine whether HP infection was a risk factor for constipation in patients with PD.

METHODS

A total of 932 PD patients with 13C-urea breath test for HP were included in the study. The PSM was estimated with the use of a nonparsimonious multivariate logistic regression model, with HP infection as the dependent variable and all the baseline characteristics as covariates. A total of 697 patients composed the study cohort, including 252 (36.2 %) patients in the HP-positive (HPP) group and 445 (63.8 %) patients in the HP-negative (HPN) group. Before PSM, there were differences in several of the baseline variables between the two groups. After PSM, 250 HPP patients were matched with 250 HPN patients and the standardized differences were less than 0.1 for all variables.

RESULTS

The present results demonstrate that HP infection is a risk factor for constipation in patients with PD [RR (95 % CI) 1.412 (1.155-1.727), P < 0.001]. Subgroup analyses revealed that HP infection was both a risk factor for constipation in Hoehn-Yahr scale (1,1.5) group and Hoehn-Yahr scale (2-5) group [OR (95 % CI) 1.811 (1.079-3.038), P < 0.025; OR (95 % CI) 2.041 (1.177-3.541), P < 0.011].

CONCLUSIONS

The results of our prospective cohort study suggest that Helicobacter pylori infection is a risk factor for constipation in patients with PD.

TRIAL REGISTRATION

ChiCTR2300071631.

Targets to Search for New Pharmacological Treatment in Idiopathic Parkinson's Disease According to the Single-Neuron Degeneration Model

One of the biggest problems in the treatment of idiopathic Parkinson's disease is the lack of new drugs that slow its progression. L-Dopa remains the star drug in the treatment of this disease, although it induces severe side effects. The failure of clinical studies with new drugs depends on the use of preclinical models based on neurotoxins that do not represent what happens in the disease since they induce rapid and expansive neurodegeneration. We have recently proposed a single-neuron degeneration model for idiopathic Parkinson's disease that requires years to accumulate enough lost neurons for the onset of motor symptoms. This single-neuron degeneration model is based on the excessive formation of aminochrome during neuromelanin synthesis that surpass the neuroprotective action of the enzymes DT-diaphorase and glutathione transferase M2-2, which prevent the neurotoxic effects of aminochrome. Although the neurotoxic effects of aminochrome do not have an expansive effect, a stereotaxic injection of this endogenous neurotoxin cannot be used to generate a preclinical model in an animal. Therefore, the aim of this review is to evaluate the strategies for pharmacologically increasing the expression of DT diaphorase and GSTM2-2 and molecules that induce the expression of vesicular monoamine transporter 2, such as pramipexole.

Intensive training programme improves handwriting in a community cohort of people with Parkinson's disease

BACKGROUND

People with Parkinson's disease (PwP) often report problems with their handwriting before they receive a formal diagnosis. Many PwP suffer from deteriorating handwriting throughout their illness, which has detrimental effects on many aspects of their quality of life.

AIMS

To assess a 6-week online training programme aimed at improving handwriting of PwP.

METHODS

Handwriting samples from a community-based cohort of PwP (n = 48) were analysed using systematic detection of writing problems (SOS-PD) by two independent raters, before and after a 6-week remotely monitored physiotherapy-led training programme. Inter-rater variability on multiple measures of handwriting quality was analysed. The handwriting data was analysed using pre-/post-design in the same individuals. Multiple aspects of the handwriting samples were assessed, including writing fluency, transitions between letters, regularity in letter size, word spacing, and straightness of lines.

RESULTS

Analysis of inter-rater reliability showed high agreement for total handwriting scores and letter size, as well as speed and legibility scores, whereas there were mixed levels of inter-rater reliability for other handwriting measures. Overall handwriting quality (p = 0.001) and legibility (p = 0.009) significantly improved, while letter size (p = 0.012), fluency (p = 0.001), regularity of letter size (p = 0.009), and straightness of lines (p = 0.036) were also enhanced.

CONCLUSIONS

The results of this study show that this 6-week intensive remotely-monitored physiotherapy-led handwriting programme improved handwriting in PwP. This is the first study of its kind to use this tool remotely, and it demonstrated that the SOS-PD is reliable for measuring handwriting in PwP.

Clinical characteristics and reaction to dopaminergic treatment of drug-naïve patients with Parkinson's disease in central China: A cross sectional study

Background

The symptoms of early Parkinson's disease (PD) are complex and hidden. The aim of this study is to explore and summarize the characteristics of the symptoms of drug naïve patients with PD.

Objectives

and Methods Drug-naïve patients with PD and age-matched healthy controls were recruited from the outpatient clinic of Wuhan Union Hospital. The motor and non-motor symptoms were evaluated for further analysis using Unified Parkinson's Disease Rating Scale (UPDRS) I, II, and III; Sniffin' Sticks Screening 12 test; Mini-Mental State Exam (MMSE); Montreal Cognitive Assessment (MoCA); Hamilton Anxiety Scale (HAMA); and Hamilton Depression Scale (HAMD) scores. The acute levodopa challenge test (ALCT) was adopted to assess the reaction to dopaminergic treatment.

Results

We recruited 80 drug-naïve patients with PD and 40 age-matched healthy controls (HCs). Approximately 53.7% of the patients were females. The mean onset age was 59.96 ± 10.40 years. The mean UPDRS I, II, and III were 2.01 ± 1.90, 6.18 ± 3.68, and 26.13 ± 12.09, respectively. Compared with HCs, PD patients had lower scores in MMSE and MoCA; and higher scores in HAMA and HAMD (p < 0.05). In ALCT, 54 patients showed good responses to levodopa while 26 patients did not. The mean improvement rate of UPDRS III was 34.09% at 120 min.

Conclusion

The motor symptoms of patients with early PD were mild but virous. They also suffered from different non-motor symptoms. In ALCT, about two thirds of patients (54/80) with early PD showed good response to levodopa. Among four aspects of motor symptoms, bradykinesia reacted best to ALCT, while axial symptoms were the worst.

Dopamine D1 Agonists: First Potential Treatment for Late-Stage Parkinson's Disease

Current pharmacotherapy has limited efficacy and/or intolerable side effects in late-stage Parkinson's disease (LsPD) patients whose daily life depends primarily on caregivers and palliative care. Clinical metrics inadequately gauge efficacy in LsPD patients. We explored if a D1/5 dopamine agonist would have efficacy in LsPD using a double-blind placebo-controlled crossover phase Ia/b study comparing the D1/5 agonist PF-06412562 to levodopa/carbidopa in six LsPD patients. Caregiver assessment was the primary efficacy measure because caregivers were with patients throughout the study, and standard clinical metrics inadequately gauge efficacy in LsPD. Assessments included standard quantitative scales of motor function (MDS-UPDRS-III), alertness (Glasgow Coma and Stanford Sleepiness Scales), and cognition (Severe Impairment and Frontal Assessment Batteries) at baseline (Day 1) and thrice daily during drug testing (Days 2-3). Clinicians and caregivers completed the clinical impression of change questionnaires, and caregivers participated in a qualitative exit interview. Blinded triangulation of quantitative and qualitative data was used to integrate findings. Neither traditional scales nor clinician impression of change detected consistent differences between treatments in the five participants who completed the study. Conversely, the overall caregiver data strongly favored PF-06412562 over levodopa in four of five patients. The most meaningful improvements converged on motor, alertness, and functional engagement. These data suggest for the first time that there can be useful pharmacological intervention in LsPD patients using D1/5 agonists and also that caregiver perspectives with mixed method analyses may overcome limitations using methods common in early-stage patients. The results encourage future clinical studies and understanding of the most efficacious signaling properties of a D1 agonist for this population.

Characterization of nonmotor behavioral impairments and their neurochemical mechanisms in the MitoPark mouse model of progressive neurodegeneration in Parkinson's disease

Mitochondrial dysfunction has been implicated as a key player in the pathogenesis of Parkinson's disease (PD). The MitoPark mouse, a transgenic mitochondrial impairment model developed by specific inactivation of TFAM in dopaminergic neurons, spontaneously exhibits progressive motor deficits and neurodegeneration, recapitulating several features of PD. Since nonmotor symptoms are now recognized as important features of the prodromal stage of PD, we comprehensively assessed the clinically relevant motor and nonmotor deficiencies from ages 8-24 wk in both male and female MitoPark mice and their littermate controls. As expected, motor deficits in MitoPark mice began around 12-14 wk and became severe by 16-24 wk. Interestingly, MitoPark mice exhibited olfactory deficits in the novel and social scent tests as early as 10-12 wk as compared to age-matched littermate controls. Additionally, male MitoPark mice showed spatial memory deficits before female mice, beginning at 8 wk and becoming most severe at 16 wk, as determined by the Morris water maze. MitoPark mice between 16 and 24 wk spent more time immobile in forced swim and tail suspension tests, and made fewer entries into open arms of the elevated plus maze, indicating a depressive and anxiety-like phenotype, respectively. Importantly, depressive behavior as determined by immobility in forced swim test was reversible by antidepressant treatment with desipramine. Neurochemical and mechanistic studies revealed significant changes in CREB phosphorylation, BDNF, and catecholamine levels as well as neurogenesis in key brain regions. Collectively, our results indicate that MitoPark mice progressively exhibit deficits in olfactory discrimination, cognitive learning and memory, and anxiety- and depression-like behaviors as well as key neurochemical signaling associated with nonmotor deficits in PD. Thus, MitoPark mice can serve as an invaluable model for studying nonmotor deficits in addition to studying the motor deficits related to pathology in PD.

Spinal cord involvement in Lewy body-related α-synucleinopathies

Context: Lewy body (LB)-related α-synucleinopathy (LBAS) is the neuropathological hallmark of several neurodegenerative diseases such as Parkinson disease (PD), but it is also found in neurologically asymptomatic subjects. An abnormal accumulation of α-synuclein has been reported also in the spinal cord, but extent and significance of the spinal cord involvement are still poorly defined. Objective: We aimed to review the studies addressing the spinal cord involvement of LBAS in healthy subjects and in patients with PD or other neurodegenerative diseases. Methods: A MEDLINE search was performed using following terms: "spinal cord", " α-synucleinopathy", "α-synuclein", "Lewy body", "Parkinson's disease", "multiple system atrophy", "neurodegenerative disorder". Results: LBAS in the spinal cord is associated with that of the medullary reticular formation and locus ceruleus in the brainstem but not with that in the olfactory bulb and amygdala. The intermediolateral columns of the thoracic and sacral cord are the most frequently and severely affected region of the spinal cord. LBAS occurs in centrally projecting spinal cord neurons integrating pain, in particular from lower body periphery. It also involves the sacral parasympathetic nucleus innervating the smooth muscles of the bladder and distal colon and the Onuf's nucleus innervating the striated sphincters. The spinal cord lesions may thus play a crucial role in the genesis of frequent non-motor symptoms such as pain, urinary symptoms, bowel dysfunction, autonomic failure including orthostatic hypotension and sexual disturbances. Moreover, these may also contribute to the motor symptoms, since α-synuclein inclusions have been observed in the pyramidal tracts of patients with PD and multiple system atrophy. Conclusion: Recognition of this peculiar spinal cord pathology may help in the management of the related symptoms in subjects affected by α-synucleinopathies.

The contribution of Parkin, PINK1 and DJ-1 genes to selective neuronal degeneration in Parkinson's disease

Parkinson's disease (PD) is characterised by selective and severe degeneration of the substantia nigra pars compacta and the locus coeruleus (LC), which underlies the most prominent symptoms. Although α-synuclein accumulation has long been established to play a causal role in the disease, it alone cannot explain the selective degenerative pattern. Recent evidence shows that the selective vulnerability could arise due to the large presence of cytosolic catecholamines and Ca2+ ions in the substantia nigra pars compacta and LC specifically that can be aberrantly affected by α-synuclein accumulation. Moreover, each has its own toxic potential, and disturbance of one can exacerbate the toxic effects of the others. This presents a mechanism unique to these areas that can lead to a vicious degenerative cycle. Interestingly, in familial variants of PD, the exact same brain areas are affected, implying the underlying process is likely the same. However, the exact disease mechanisms of many of these genetic variants remain unclear. Here, we review the effects of the PD-related genes Parkin, PINK1 and DJ-1. We establish that these mutant varieties can set in motion the same degenerative process involving α-synuclein, cytosolic catecholamines and Ca2+ . Additionally, we show indications that model organisms might not accurately represent all components of this central mechanism, explaining why Parkin, PINK1 and DJ-1 model organisms often lack a convincing PD-like phenotype.

Neuropsychiatric aspects of Parkinson disease psychopharmacology: Insights from circuit dynamics

Parkinson disease (PD) is a neurodegenerative disorder with a complex pathophysiology characterized by the progressive loss of dopaminergic neurons within the substantia nigra. Persons with PD experience several motoric and neuropsychiatric symptoms. Neuropsychiatric features of PD include depression, anxiety, psychosis, impulse control disorders, and apathy. In this chapter, we will utilize the National Institutes of Mental Health Research Domain Criteria (RDoC) to frame and integrate observations from two prevailing disease constructions: neurotransmitter anomalies and circuit physiology. When there is available evidence, we posit how unified translational observations may have clinical relevance and postulate importance outside of PD. Finally, we review the limited evidence available for pharmacologic management of these symptoms.

Exploring white matter microstructure and olfaction dysfunction in early parkinson disease: diffusion MRI reveals new insight

Olfaction dysfunction is considered as a robust marker of prodromal Parkinson disease (PD). Measurement of olfaction function as a screening test is unsatisfactory due to long lead time interval and low specificity for detection of PD. Use of imaging markers might yield more accurate predictive values and provide bases for combined use of imaging and clinical markers for early PD. Diffusion MRI connectometry was conducted on 85 de novo PD patients in and 36 healthy controls to find: first, white matter tracts with significant difference in quantitative anisotropy between PD groups with various degrees of olfaction dysfunction and second, second fibers with correlation with University of Pennsylvania Smell Identification Test (UPSIT) score in each group using a multiple regression analysis considering age, sex, GDS and MoCA score. Local connectomes were determined in seven of all the possible comparisons, correcting for false discovery rate (FDR). PD patients with anosmia and normal olfaction had the highest number of fibers with decreased connectivity in left inferior longitudinal fasciculus, bilateral fornix, bilateral middle cerebellar peduncle (MCP), bilateral cingulum, bilateral corticospinal tract (CST) and body, genu and splenium of corpus callosum (CC) (FDR = 0.0013). In multiple regression analysis, connectivity in the body, genu and splenium of CC and bilateral fornix had significant negative correlation (FDR between 0.019 and 0.083), and bilateral cingulum and MCP had significant positive correlation (FDR between 0.022 and 0.092) with UPSIT score. White matter connectivity in healthy controls could not be predicted by UPSIT score using the same model. The results of this study provide compelling evidence that microstructural degenerative changes in these areas underlie the clinical phenotype of prodromal olfaction dysfunction in PD and that diffusion parameters of these areas might be able to serve as signature markers for early detection of PD. This is the first report that confirms a discriminative role for UPSIT score in identifying PD specific changes in white matter microstructure. Our results open a window to identify microstructural signatures of prodromal PD in white matter.

Hyposmia as a Predictive Marker of Parkinson's Disease: A Systematic Review and Meta-Analysis

Background

Hyposmia is one of the most common and best-characterized conditions that is also one of the first nonmotor features of Parkinson's disease (PD). The association of hyposmia with PD is widely accepted; however the likelihood of developing PD is unclear. Our meta-analysis aimed to investigate the risk of PD in individuals with hyposmia.

Methods

Prospective studies on humans published before December 4^th, 2018, were searched for in PubMed, Embase, Web of Science, and Cochrane Library databases. Two independent reviewers screened studies for inclusion and extracted data. We assessed the quality of studies using the Newcastle–Ottawa Scale and pooled data for analysis using random-effects models.

Results

Of the 1774 studies retrieved, seven met the inclusion criteria for this review. A total of 3272 hyposmia and 176 PD events were reported over follow-up periods ranging from 3 to 17 years. Hyposmia was associated with a 3.84-fold risk of developing PD (pooled relative risk: 3.84, 95% CI 2.12−6.95). Subgroup analyses identified few differences between different hyposmia assessment methodologies and follow-up periods.

Conclusions

Our findings suggest that deficiencies in olfaction are associated with an increased risk of developing PD. Future studies are needed to investigate whether hyposmia is a promising and feasible biomarker for the early diagnosis of PD.

Depression and risk of cognitive dysfunctions in amyotrophic lateral sclerosis

OBJECTIVES

Amyotrophic lateral sclerosis (ALS) is not only a motor disorder: More than 50% of patients have cognitive dysfunctions over the course of the disease. At the same time, mood disorders may also occur in ALS patients following diagnosis due to the fatal prognosis; however, little data are available on any depression beforehand. Starting from these considerations, the aim of our study was to investigate the occurrence of depression in Italian ALS patients prior to diagnosis, evaluating its prevalence in the subjects who have developed cognitive dysfunctions and in those who did not.

MATERIALS AND METHODS

We included 318 patients, establishing the presence of depression in the 5 years before ALS diagnosis. Patients underwent a complete battery of neuropsychological tests with the aim to evaluate the executive functions, behavior, language, and memory.

RESULTS

Before diagnosis, 40 patients with ALS had been diagnosed with depression: Among them, 29 patients had cognitive impairment over the course of the disease and only 11 did not develop any cognitive alteration (OR 1.46; 95% CI: 1.26-1.66, adjusted for sex, age, and disease phenotype, P: 0.038). Moreover, there is a significant difference in survival time between ALS patients with depression before ALS, compared to ALS patients without previous depression (P: 0.006).

CONCLUSIONS

We reported a high prevalence of depression in the past in patients with ALS and cognitive impairment, as compared to patients without cognitive deficits, showing also that patients with both had a shorter survival time. These aspects require multidisciplinary approach at disease onset.

Exercise as a therapeutic intervention for motor and non-motor symptoms in Parkinson's disease: Evidence from rodent models

Parkinson's disease (PD) is characterised by degeneration of dopaminergic neurons of the nigrostriatal pathway, which leads to the cardinal motor symptoms of the disease - tremor, rigidity and postural instability. A number of non-motor symptoms are also associated with PD, including cognitive impairment, mood disturbances and dysfunction of gastrointestinal and autonomic systems. Current therapies provide symptomatic relief but do not halt the disease process, so there is an urgent need for preventative strategies. Lifestyle interventions such as aerobic exercise have shown potential to lower the risk of developing PD and to alleviate both motor and non-motor symptoms. However, there is a lack of large-scale randomised clinical trials that have employed exercise in PD patients. This review will focus on the evidence from studies on rodent models of PD, for employing exercise as an intervention for both motor and non-motor symptoms.

Alpha-synuclein overexpression in the olfactory bulb initiates prodromal symptoms and pathology of Parkinson's disease

Background

Parkinson's disease (PD) is a neurodegenerative disease characterized by intraneuronal Lewy Body (LB) aggregates composed of misfolded alpha-synuclein (α-syn). The spread of misfolded α-syn follows a typical pattern: starting in the olfactory bulb (OB) and the gut, this pathology is followed by the progressive invasion of misfolded α-syn to the posterior part of the brain. It is unknown whether the administration of human mutant alpha-synuclein (hm-α-syn, a human mutation which occurs in familial PD) into the OB of rats would trigger similar α-syn propagation and subsequently cause pathological changes in broader brain fields associated to PD and establish an animal model of prodromal PD.

Methods

hm-α-syn was overexpressed in the OB of rats with an AAV injection. Then motor and non-motor symptoms of the SD rats were tested in different behavioral tasks following the AAV injection. In follow-up studies, pathological mechanisms of α-syn spread were explored at the histological, biochemical and micro-structure levels.

Results

The experimental results indicated that hm-α-syn was overexpressed in the OB 3 weeks after the AAV injection. 1) overexpression of the Hm-α-syn in the OB by the AAV injection could transfer to wider adjacent fields beyond the monosynaptic scope. 2) The number of tyrosine hydroxylase positive cells body and fibers was decreased in the substantia nigra (SN) 12 weeks after AAV injection. This was consistent with decreased levels of the DA neurotransmitter. Importantly, behavioral dysfunctions were found that included olfactory impairment after 3 weeks, motor ability impairment and decreased muscular coordination on a rotarod 6 weeks after the AAV injection.3) The morphological level studies found that the Golgi staining revealed the number of neuronal branches and synapses in the OB, prefrontal cortex (PFC), hippocampus (Hip) and striatum caudate putamen (CPU) were decreased. 4) phosphorylated α-syn, at Ser-129 (pSer129), was found to be increased in hm-α-syn injected animals in comparison to controls that overexpressed GFP alone, which was also found in the most of LB stained by the thioflavine S (ThS) in the SN field. 5) A marker of autophagy (LC3B) was increased in serval fields, which was colacolizated with a marker of apoptosis in the SN field.

Conclusions

These results demonstrate that expression of exogenous mutant α-syn in the OB induces pathological changes in the sensitive brain fields by transferring pathogenic α-syn to adjacent fields. This method may be useful for establishing an animal model of prodromal PD.

Analysis of the clinical features of early Parkinson's disease with comparatively integrated intestinal function

OBJECTIVE

Constipation is among the most frequently delineated nonmotor symptoms (NMS) with a high occurrence in Parkinson's disease (PD). The purpose of our study was to investigate whether PD with comparatively integrated intestinal function (without constipation) in the early stage had different clinical features compared to constipated PD.

METHOD

We conducted a study of 105 consecutive de novo as well as early treated (treated for shorter than 3 months), aged 50 years or older outpatients. Subjects were administered motor and nonmotor questionnaires as well as constipation associated examinations. Then, we explored the distinctive features of nonconstipated contrasted to constipated PD by using univariate, multiple regression analysis and correlation analysis.

RESULTS

Nonconstipated PD tended to have fewer motor deficits, as well as lower Hoehn and Yahr (H&Y) stage and they mainly presented as tremor-dominant (TD), while constipated group had a higher occurrence of posture instability and gait difficulty (PIGD); nonconstipated patients were inclined to live in urban area, the NMSloads and prevalence of NMS were lower compared to constipated ones. Correlation analysis found a discord between NMSloads and disease severity based on H&Y stage and motor scores in nonconstipated PD.

CONCLUSIONS

These results suggest that PD without constipation in early stage may represent a unique clinical phenotype, which may be more benign than PD with constipation.

Rapid eye movement sleep behavior disorder and the link to alpha-synucleinopathies

Rapid eye movement (REM) sleep behavior disorder (RBD) involves REM sleep without atonia in conjunction with a recurrent nocturnal dream enactment behavior, with vocalizations such as shouting and screaming, and motor behaviors such as punching and kicking. Secondary RBD is well described in association with neurological disorders including Parkinson's disease (PD), multiple system atrophy (MSA), and other conditions involving brainstem structures such as tumors. However, RBD alone is now considered to be a potential harbinger of later development of neurodegenerative disorders, in particular PD, MSA, dementia with Lewy bodies (DLB), and pure autonomic failure. These conditions are linked by their underpinning pathology of alpha-synuclein protein aggregation. In RBD, it is therefore important to recognize the potential risk for later development of an alpha-synucleinopathy, and to investigate for other potential causes such as medications. Other signs and symptoms have been described in RBD, such as orthostatic hypotension, or depression. While it is important to recognize these features to improve patient management, they may ultimately provide clinical clues that will lead to risk stratification for phenoconversion. A critical need is to improve our ability to counsel patients, particularly with regard to prognosis. The ability to identify who, of those with RBD, is at high risk for later neurodegenerative disorders will be paramount, and would in addition advance our understanding of the prodromal stages of the alpha-synucleinopathies. Moreover, recognition of at-risk individuals for neurodegenerative disorders may ultimately provide a platform for the testing of possible neuroprotective agents for these neurodegenerative disorders.

Do subjects with minimal motor features have prodromal Parkinson disease?

OBJECTIVE

Understanding the pathological changes underlying mild motor features of the eldery and defining a patient population with prodromal Parkinson disease (PD) are of great clinical importance. It remains unclear, however, how to accurately and specifically diagnose prodromal PD. We examined whether older adults with minimal parkinsonian motor features have nigrostriatal degeneration and α-synuclein pathology consistent with prodromal PD.

METHODS

Brain sections were obtained from older adults with a clinical diagnosis of PD (n = 21) and without a clinical diagnosis of PD (n = 27) who underwent motor examination proximate to death. Cases without PD were further dichotomized into no motor deficit (n = 9) or minimal motor features (n = 18) groups using a modified Unified Parkinson's Disease Rating Scale. We performed quantitative unbiased stereological analyses of dopaminergic neurons/terminals and α-synuclein accumulation in the nigrostriatal system.

RESULTS

In all subjects with minimal motor features, there were significant reductions in dopaminergic neurons and terminals in the substantia nigra and putamen that were intermediate between subjects with no motor deficit and PD. Phosphorylated α-synuclein inclusions were observed in the substantia nigra that were of similar density to what was seen in PD. Furthermore, there was greater Lewy neuritic pathology in the putamen relative to PD patients. Lastly, neurons with α-synuclein inclusions displayed reductions in tyrosine hydroxylase expression that were comparable in subjects with both minimal motor features and PD.

INTERPRETATION

Minimal motor features in older adults may represent prodromal PD and identify at-risk individuals for testing putative neuroprotective interventions that could slow or prevent PD progression. Ann Neurol 2018;83:562-574.

Biological and Clinical Implications of Comorbidities in Parkinson's Disease

A wide spectrum of comorbidities has been associated with Parkinson's disease (PD), a progressive neurodegenerative disease that affects more than seven million people worldwide. Emerging evidence indicates that chronic diseases including diabetes, depression, anemia and cancer may be implicated in the pathogenesis and progression of PD. Recent epidemiological studies suggest that some of these comorbidities may increase the risk of PD and precede the onset of motor symptoms. Further, drugs to treat diabetes and cancer have elicited neuroprotective effects in PD models. Nonetheless, the mechanisms underlying the occurrence of these comorbidities remain elusive. Herein, we discuss the biological and clinical implications of comorbidities in the pathogenesis, progression, and clinical management, with an emphasis on personalized medicine applications for PD.

Neuropathology of Nonmotor Symptoms of Parkinson's Disease

Parkinson's disease (PD), a multiorgan neurodegenerative disorder associated with α-synuclein deposits throughout the nervous system and many organs, is clinically characterized by motor and nonmotor features, many of the latter antedating motor dysfunctions by 20 or more years. The causes of the nonmotor manifestations such as olfactory, autonomic, sensory, neuropsychiatric, visuospatial, sleep, and other disorders are unlikely to be related to single lesions. They are mediated by the involvement of both dopaminergic and nondopaminergic systems, and diverse structures outside the nigrostriatal system that is mainly responsible for the motor features of PD. The nonmotor alterations appear in early/prodromal stages of the disease and its further progression, suggesting a topographical and chronological spread of the lesions. This lends further support for the notion that PD is a multiorgan proteinopathy, although the exact relationship between presymptomatic and later developing nonmotor features of PD and neuropathology awaits further elucidation.

Integrated analysis of genetic, behavioral, and biochemical data implicates neural stem cell-induced changes in immunity, neurotransmission and mitochondrial function in Dementia with Lewy Body mice

We previously demonstrated that transplantation of murine neural stem cells (NSCs) can improve motor and cognitive function in a transgenic model of Dementia with Lewy Bodies (DLB). These benefits occurred without changes in human α-synuclein pathology and were mediated in part by stem cell-induced elevation of brain-derived neurotrophic factor (BDNF). However, instrastriatal NSC transplantation likely alters the brain microenvironment via multiple mechanisms that may synergize to promote cognitive and motor recovery. The underlying neurobiology that mediates such restoration no doubt involves numerous genes acting in concert to modulate signaling within and between host brain cells and transplanted NSCs. In order to identify functionally connected gene networks and additional mechanisms that may contribute to stem cell-induced benefits, we performed weighted gene co-expression network analysis (WGCNA) on striatal tissue isolated from NSC- and vehicle-injected wild-type and DLB mice. Combining continuous behavioral and biochemical data with genome wide expression via network analysis proved to be a powerful approach; revealing significant alterations in immune response, neurotransmission, and mitochondria function. Taken together, these data shed further light on the gene network and biological processes that underlie the therapeutic effects of NSC transplantation on α-synuclein induced cognitive and motor impairments, thereby highlighting additional therapeutic targets for synucleinopathies.

Microbiota-gut-brain signalling in Parkinson's disease: Implications for non-motor symptoms

Parkinson's disease is the second most common neurodegenerative disorder, affecting 1-2% of the population over 65 years of age. The primary neuropathology is the loss of midbrain dopaminergic neurons, resulting in characteristic motor deficits, upon which the clinical diagnosis is based. However, a number of significant non-motor symptoms (NMS) are also evident that appear to have a greater impact on the quality of life of these patients. In recent years, it has become increasingly apparent that neurobiological processes can be modified by the bi-directional communication that occurs along the brain-gut axis. The microbiota plays a key role in this communication throughout different routes in both physiological and pathological conditions. Thus, there has been an increasing interest in investigating how microbiota changes within the gastrointestinal tract may be implicated in health and disease including PD. Interestingly α-synuclein-aggregates, the cardinal neuropathological feature in PD, are present in both the submucosal and myenteric plexuses of the enteric nervous system, prior to their appearance in the brain, indicating a possible gut to brain route of "prion-like" spread. In this review we highlight the potential importance of gut to brain signalling in PD with particular focus on the role of the microbiota as major player in this communication.